Is AES/EBU the same as XLR?

An AES/EBU cable is spec'd at 110 ohms, a regular cable with XLR ends may or may not have that spec. You can still use any XLR cable, but it will not provide an optimal transfer of digital data.

I second Onhwy61.
The same applies for RCA terminated digital interconnects. They have to be 75 Ohms.
Thus any digital RCA interconnect may be used for analog duty, but not the other way around. Well, one could use an analog interconnect for digital duty, it will "work", but the sound quality will suffer from reflection-induced jitter if the cable is not 75 Ohms.
In the XLR world the same applies, only the required characteristic impedance is different.

Thank you for your answers. They are helpful.

i will add that my favorite audio buy ever is the van den hul first cable used as a digital interconnect, which is pertinent in that i don't believe that it's the recommended 75 ohms. i bought it as an analog interconnect, but after reading that some people used it as a digital cable i gave it a go and loved it. been itchin' to try my vdh "second" cables as digital interconnects, but i don't have any xlr digital stuff.

so you never know what will sound good.

'so you never know what will sound good.'

I second that! Have often been surprised. Give it a go and let us know.